function [output]=figure_pointabsorbing()
[x1,y1] = meshgrid(-8:16:8);
z1 = x1+y1/3;
surf(x1,y1,z1,'FaceColor','cyan','FaceAlpha',0.5);
hold on;
x2 = x1;
y2 = y1;
z2 = 6-x2/2-y2/6;
surf(x2,y2,z2,'FaceColor','yellow','FaceAlpha',0.5);
hold on;
nx = linspace(-4,4,10);
ny = nx./3; 
nz = -nx;
%plot3(nx,ny,nz, 'Color', 'black', 'LineWidth', 2);
%hold on;
px = randint(1, 40, [-8, 8]);
py = randint(1, 40, [-8, 8]);
pz = px+py/3;
px2 = randint(1, 15, [-8, 8]);
py2 = randint(1, 15, [-10, 10]);
pz2 = randint(1, 15, [-20, 20]);
px = [px, px2];
py = [py, py2];
pz = [pz, pz2];
plot3(px,py,pz,'.', 'MarkerSize', 6);
hold on;
qx =-8;
qy = -3;
qz = 8;
plot3(qx,qy,qz, 'bo', 'MarkerSize', 6);
hold on;
ds1 = linspace(0,8,10);
ds1_x = qx+ds1;
ds1_y = qy+ds1./3;
ds1_z = qz-ds1;
ds2 = linspace(0,2,10);
ds2_x = qx+ds2./2;
ds2_y = qy+ds2./6;
ds2_z = qz+ds2;
plot3(ds1_x,ds1_y,ds1_z,'black','LineWidth',2);
hold on;
plot3(ds2_x,ds2_y,ds2_z,'r','LineWidth',2);
hold on;
view([-30,30]);
axis([-10 10 -10 10 -10 10 -1 1]);
grid on;
